1. Field of the Invention
This invention pertains to self-fixturing weldments and attachment mechanisms for use with bars, rods and the like for use in mechanisms such as seat guides and the like; particularly employed in automotive vehicles.
2. Brief Discussion of the Relevant Art
In linkage assemblies such as those employed in seat assembly units, torsion rod sub-assemblies can be employed to accommodate the desired movement of the seat assembly. Heretofore, the torsion rod sub-assembly was composed of an elongated member such as a bar or tube onto which perpendicularly projecting linkage members could be attached. The linkage members are composed of a metal member having an aperture positioned in a suitably flat region through which the cylindrical bar or tube can be inserted. The linkage member is welded to the elongated member at a position relative thereon. In order to achieve a successful welding operation, the weld must flow into the tight corner formed between the torsion rod and the flat surface of the linkage. This creates a less than ideal weld condition as it is difficult to flow the weld material evenly between the mating parts. This creates a potential for voids in the "corner" between the two members and can result in insecure welds on either or both of the respective surfaces.
Additionally, welding a linkage assembly of the described configuration presents a situation in which the linkage material proximate to the weld joint is more massive than the torsion tube which is being attached. When either element, i.e. the link or the torsion tube/bar, is more massive than the other, the heat of the welding operation flows unevenly toward the more massive element. This can create an uneven weld. In order to compensate for this phenomenon, additional welding heat is sometimes applied. In such situations, it is theoretically possible to burn through the less massive element resulting in undesirable part failure.
Additionally, in the assembly of mechanisms, such as linkage assemblies, it is necessary that the linkage member be positioned precisely relative to the torsion rod. Positioning of the linkage member must be both longitudinally and angularly precise relative to the torsion rod. It has been found that conventional linkage members were difficult to fixture and position during the welding process to provide the necessary angular precision relative to the torsion bar/link. The linkages had tended to "toe in" or "toe out". Imprecise positioning during the welding process can result in rejected parts if great care and precision is not taken during the assembly procedure.
Thus, it would be highly desirable to provide a linkage assembly in which the component parts are such that the disparity in mass between the linkage member and the torsion rod is eliminated or greatly reduced. Additionally, it would be desirable to provide a linkage assembly in which the various components are configured to permit greater ease in fixturing the parts relative to one another during the manufacturing process. It would be highly desirable to provide a linkage assembly which would permit secure weld seams and greater reproducability and repeatability in the welding process during manufacturing. Finally, it would be desirable to provide an automotive seat device employing such a linkage assembly.